Parent Child Hierarchical Cumulative Sum using sql server

Recently I had a complicated scenario while generating reports. I need to have each level be the sum of all children (in the hierarchy) in addition to any values set against that value itself for the amount column.
I failed to produce expected results using Linq, Thanks to SQL server, it comes to the rescue. Using CTE it's a bit easy to produce what exact result I want.
In this article, I am going to share, how to Cumulative Sum on Hierarchical level using SQL server.